Change X11 window title after emacs started

Question

When I start emacs, I can use the --title= option to control the title of the x-window that holds the emacs application. Is it possible to change the title after emacs starts f

Answer 1

The following worked for me (GNU EMACS 24.3.1 on cygwin multiwindow X11):

 (set-frame-parameter frame 'title arg)

which I wrapped in an interactive function

(defun set-frame-title/ag (title &optional frame)
  "set frame TITLE of &optional FRAME defaults to (selected-frame)
aka C11 window titlebar name"
  (interactive "sframe title: ")
  (set-frame-parameter frame 'title title)
  )

Answer 2

I use

(setq frame-title-format "%b - emacs")

to include the current buffer name in the frame title.

Answer 3

M-x set-frame-name NewName RET

and from elisp

(set-frame-name "NewName")